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Radiology. 1999 Oct;213(1):150-5.

Acute stroke: improved nonenhanced CT detection--benefits of soft-copy interpretation by using variable window width and center level settings.

Author information

1
Department of Radiology, Massachusetts General Hospital, Boston 02114-9657, USA. mlev@partners.org

Abstract

PURPOSE:

To assess the use of nonstandard, variable window width and level review settings in computed tomography (CT) without contrast material administration in the detection of acute stroke.

MATERIALS AND METHODS:

Nonenhanced CT was performed in 21 patients with acute (< 6 hours) middle cerebral arterial stroke and nine control patients. Two blinded neuroradiologists rated all scans for presence of parenchymal hypoattenuation. Images were reviewed at a picture archiving and communication system (PACS) workstation, with standard, locally determined center level and window width settings of 20 and 80 HU and with variable soft-copy settings initially centered at a level of 32 HU with a width of 8 HU. Reviewers altered settings to accentuate gray and white matter contrast.

RESULTS:

With standard viewing parameters, sensitivity and specificity for stroke detection were 57% and 100%. Sensitivity increased to 71% with variable window width and center level settings, without loss of specificity. Receiver operating characteristic analysis revealed a significant improvement in accuracy with nonstandard, soft-copy review settings (P = .03, one-tailed z test).

CONCLUSION:

In nonehanced CT of the head, detection of ischemic brain parenchyma is facilitated by soft-copy review with variable window width and center level settings to accentuate the contrast between normal and edematous tissue.

[Indexed for MEDLINE]

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